Is plasma oxidized low-density lipoprotein, measured with the widely used antibody 4E6, an independent predictor of coronary heart disease among U.S. men and women?

OBJECTIVES Our aim was to examine whether circulating oxidized low-density lipoprotein (oxLDL) is a predictor of coronary heart disease (CHD) independent of lipid markers and to compare oxLDL, apolipoprotein B100 (apoB), and total cholesterol (TC)/high-density lipoprotein-cholesterol (HDL-C) ratio as predictors of CHD. BACKGROUND Measurement of circulating oxLDL with antibody 4E6, has been widely used in many studies; however, few large prospective studies have examined whether this marker is a predictor of CHD independent of lipids and compared oxLDL with other important lipid predictors. METHODS After 6 years of follow-up among 18,140 men from the HPFS (Health Professionals Follow-up Study) and 8 years among 32,826 women from the Nurses' Health Study who provided blood samples at baseline, we identified incident nonfatal myocardial infarction or fatal CHD in 266 men and 235 women. Each case was matched with two control subjects by age, smoking, and time of blood draw. The oxLDL was measured via enzyme-linked immunosorbent assay with antibody 4E6 against oxidized apoB. RESULTS Among both men and women, oxLDL was significantly related to risk of CHD in multivariate analysis before adjustment for any lipid markers. However, when oxLDL, LDL cholesterol, HDL-C, and triglycerides were mutually adjusted, oxLDL was no longer predictive. When oxLDL and apoB were mutually adjusted, only apoB was predictive of CHD. Similar results were found when oxLDL and TC/HDL-C ratio were mutually adjusted. CONCLUSIONS Our results suggest that circulating oxLDL, measured with antibody 4E6, is not an independent overall predictor of CHD after adjustment of lipid markers and is less predictive in development of CHD than apoB and TC/HDL-C ratio.